Multistage pump



Nov. 20, 1928.I

W. C. DOWD MULTISTAGE PUMP med Aug. 15. 1924 5 Shgets-Sheet 1 ATTORNEYS w. c. ll: owl:

HULTISTAGE PUMP Filed Aug. 15, lg 3 Sheets-Sheet 2 o Q o' @-10 O IN V EN TOR Wmw.

ATTORNEYS Nov. 20, 1928. 1,692,291

w. c. Down l MULTISTAGE PMP Filed Aug. 15, 1924 3 Sheets-Sheet 3 Patented Nov. 20, 1928.

UNITED STATES v'WILLIAM CHARLES DOWD, 0F QUINCY, ILLINOIS.

MUL'rIs'rAGn BUMP.

-`A`pp1ication led August 15, 1924. Serial No. 732,282.

My invention relatos-to improvements in multi-stage pumps and it consists in the combinations, constructions, and arrangements herein described and claimed; An object of my invention is to provide aV pump of the character described in which means is provided for overcoming the ob- `iection found in the ordinary type of water pump by the improper coverting of the velocity of the water after it leaves the impeller rim into pressure before it reaches the eye of the next impeller.

A further object'of my invention is to rovide a pump in which means is provided or causing the velocity of water as it leaves t-he impeller to decrease, thereby increasing the pressure as thetwater approaches the eye of the next impeller, or deliveryport.

A further Object -of my invention is to rovide Va pump of the characterfdescribed 1n which the standard type of propeller or propeller shaft may be employed. y

A further object of my invention is to provide a pump of the character described in which a novel arrangement of the return water pipe from the automatic balance to the suction end of the pump is provided This pipe is installed in such a manner as to preclude the presenceof eddy currents set up by thek rotating water in the'suction end ofthe pump.`

A' further' object of my yinvention is to4 provide a pump of the character described v that is extremely efficient in operation,sim

, ple in construction and which is thoroughly practical for the purpose intended.

Other objects and advantages Y will appear in the following specification, and the novel features of the invention will beparticularly pointed out in the appended claim.

My invention is illustrated in the accompanying drawings forming a part of this application in which- Figure 1 is a sectional view of an embodiment of my invention.

Figure 2 is a top plane view of the lower portion of the pump casing,

Figure 3 is an end elevation of the mechanisln illustrated in Figure Figure 4 is a sectional view along the line 4-4 of Figure 1, and y Figure 5 is an `irregular sectional' view of the pump, showing the peculiar cross sectional contour of the adjacent stages and volute.

Vthe impeller.

Incarrying out my inventiaon I make use ofthe .ordinary type ofimpeller shaft 1 rotatably mounted in bearing-portions 2 of a pump casingA, The casing Af` is `composed of an upperandlower section 3 and 4, respectively.- These sections are secured i to one Aanothery by the provision of `bolts `5 projected through aligned openings y6 and Vcontacting' flange portions y7 of the sections 3 and 4. l

l The casing Afis divided bers in the present form of my invention, which I'sh'alll hereinafter refer to as stages. These stages are indicated at 8, 9,- and 10, respectively. V

Imp'ellers 11, 12, and 13 arecarried by int-o y three chaml shaftrl, and are disposed within the stages v 8, 9,fand 10, .respectivelyiof the `casing A. These impellers are provided with an eye portion 14 for the purposeof permitting the entrance of water therethrough,-so that it may be delivered at a high velocity through delivery openings 15 at the rim of The lower section 4 of the casing A- has a port 16 at one end thereof,

r f' and a delivery port 17- at the oppositeend.y Y

The delivery f port is smaller in'` diameter than the suctionl port 16,`so.that water delivered through the port 17 musty necessarily travel ata substantially" greater velocity than the entrance water would through the suction port.

In Figure 4 I have shownva sectional view of that portionof the casing ladjacenty to the delivery port and in dotted lines indicated at 18 I have shown theapproximate sectional contour of this partofthe pump. Withreferenceto Figures land 2 it will be noted thatl an ,irregular space orV double volute 2O is provided, which conducts water from the adjacent through, first, relatively small conducting portions 21 thence through .gradually increasing portions to that space immediately behind the next impeller, where the conducting area of the volute is relatively large.

The purpose of this construction is toincrease the pressure of the water as it enters the eye of the impeller, thus accomplishing a conversionV of the velocity of the water after leaving the eye `of the impeller in its travel to the eye of the next impeller.

The convolutions of vthe volutes 20 are shown mostclearly by a study of Fi lires 1 and 2', togethenfand the contour of Vt e secsA impeller chamber ico ynot present.

tions through the volutes may be seen by inspection of Figure 5.

In Figure 5 the double volutes between each of the chambers is clearly shown, and it will be noted that Water is delivered to the eye of the impeller through the volutes in opposite directions and at a diminishing velocity. Y Y

Means for preventing a whirl of the two volumesV ofwater conducted through the volutes at the eye of the adjacent impeller is proviiiled in a1 bushing 80 havingvane portions 3l extending toward-'the eyeJof the adjacent impelier. These `busl'lings are disposed in the wallbetween the chambers S and @and the adjacent volutes andserve to gather the two volumes of water atkthe eye of the succeeding impeller.

Another important feature of my inven` tion consists in the provision of a return water pipe 223 for iconductingl wat-er from the balance chamber Qlat the delivery end of the pump `to the suction chamber 23 at the suction' port 16. The connection of the freturn pipe 22 with thesuction chamberv 23 is shown at 24, and is disposed in such a positionthat the eddy current set up bythe returning water through Y the return pipe, ordinarily found in centrifugal pumps,y is In other Words, it brings the Water back into the suction end of the `pump from'lthe balancechamber in such a position that the incoming water from the suction port 16 draws in the water from the returningpipe .22 without any disturbance inthe flowI of water tothe first impeller, 15;

From the foregoing description" of the various parts of the dev-ice, the operation thereof may be readilyunderstood. operation my improved multi-stage pump operatesmuch as the ordinary type of multiV`vstage'pump, with the exception that' the use of diffusion vanes is eliminated'anda more efficient means is employed for convertingthe velocity, of the wat-er as it leaves the rim of the impeller to a. higherpressure and a lower velocity When it reaches the eye of the next impeller. This "is accomplishedsolely by the novel construction of the volutes 2() disposed between the chambers 8, 9, and l0. It has been found by actual operation,

using the same impellers and impeller shaft,

that my improved casing embodying the volute construction is 6% more efficient than the'ordinary type of single volute pump.

i Another important advantage is obtained inthe removal ofwater from the automatic balance chamber 23 to the suction end of the pump without disturbing` the movement of water to -thc irst impeller, his is accomplished by connecting the return pipewith the. suctionk chamber 2S at a point in the lower wall of the chamber just forward of the impeller shaft and inthat portion of the chamber which is greatest in capacity.

I claim:` Y j y A centrifugal pump comprising a casing, ,a plurality ofimpellers, means for actuating' said impellers, saidcasing having a double `,volute leading `from one impeller tothe eye increasing in'area as they approach the eyeL of the nent impeller, whereby aide/creasing of velocity and increasing, of pressure of the water is `effected, means for preventing whirling ofthe water as the two streams of water from the two volutes'merge into one stream, said' means comprising a bushing disposedladj acent-each of said impellers, and

deflecting varies integral `with said bushings and having concave surfacesV merginginto each other attheir adjacent extremities for directing the `flow of the two volumes of water` in one direction, whereby the two volumes of Water will.1 merge into one volume andbeconducted into `the eye of` the adjacent impeller wILniAM annelies Down. 

